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    <title>Document</title>
    <style>
        div{
            height:200px;
            width:200px;
            border:1px solid red;
            /* 线性渐变 */
            /* ○ 从上到下（默认）：background: linear-gradient(red,blue);
            ○ 从左到右：background: linear-gradient(to right,red,blue);
            ○ 对角：background: linear-gradient(to right bottom,red,blue);
            ○ 角度：background: linear-gradient(45deg,red,blue); */

            /* background-image:linear-gradient(to right bottom,red,blue,yellow) ; */
            /* background-image:linear-gradient(-45deg,red,blue,yellow) ; */
            /* background-image: repeating-linear-gradient(red 20px,blue 40px,green 60px); */
            /* background-image: repeating-linear-gradient(45deg,#fff 0px, #ffffff 25px, #000000 25px, #000000 50px);  */

            /* background-image: radial-gradient(circle at 25% 25%,red,blue);  */

            /* 径向渐变 */
            background-image:  repeating-radial-gradient(circle, #000000 0px, #000000 20px, #ffffff 20px, #ffffff 40px);
        }
    </style>
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